The present invention relates generally to the field of locking devices for underground tank fill pipes, and more particularly, is directed to a theft deterrent type of locking assembly.
It is the usual practice to store flammable liquids in underground storage tanks to provide adequate safety by minimizing the possibility of fire or explosion. In the usual gasoline service station designed for retail sale, it is the present practice to store flammable liquids such as gasoline in relatively large underground storage tanks, for example tanks of three thousand gallons to ten thousand gallons capacity or more. Most gasoline service stations dispense three or more grades or products and accordingly, multiple banks of such underground storage tanks are in common use throughout the country. Fill pipes with caps or closures lead from ground level to the underground tanks to permit easy filling of the tanks in well known manner and these fill pipes are generally easily accessible to both authorized and unauthorized personnel. Considering the price of gasoline and the number of gallons of such product which may be stored at any given location, it will be appreciated that the underground storage capacity represents a considerable investment by the service station owner. Because of the value of the underground stored product, and the generally exposed and accessible location of the service station, protective steps have to be taken to prevent or discourage theft of gasoline during the evening or other periods when most stations are closed and unattended.
In efforts to correct the problem, prior workers in the art have designed and employed locking type caps for installation over the ends of the fill pipes to prevent easy tampering with the apparatus and to discourage unauthorized removal of the stored tank contents. While the locking type fill caps have proved to be generally satisfactory, it has been found that such devices as are currently available are prone to tampering and destruction by determined thieves because of the fact that most service stations close at night and the would-be thieves have adequate time in which to destroy the locks to thereby gain entrance to the underground stored materials.
While of course almost any type of lock can be broken if the thief possesses sufficient skill, tools, determination and time within which to do the job, the need remains to provide a simply designed, relatively inexpensive tank fill locking system which can offer maximum protection against the efforts of an average gasoline thief.